Dream Weavers: How Acura Assembles Its New NSX Supercar

Don Sherman

Mar 17, 2016

Surrounded by farm fields, 108 Honda folks are building supercars in rural Ohio; the glass doors exiting the Performance Manufacturing Center (PMC) lobby located near Pottersburg, Ohio, are etched with one huge but inscrutable Japanese Kanji character. At the bottom, the word “dream” decodes that message for those fortunate enough to pass through this portal to the plant floor.

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“Dream” says it all. That word is stitched throughout Honda’s and Acura’s history because it concisely defines founder Soichiro Honda’s spirit, successfully passed down to the Buckeye team building new Acura NSXs.

Honda became the world’s largest motorcycle brand in 1959, only a decade after introducing the Dream D-type, the first product designed entirely in-house. What better time to borrow $1 million from Japan’s Ministry of Finance to set up shop in the land of the free? Against the wishes of another Japanese ministry—that of International Trade and Industry—Honda progressed from two to four wheels in 1963. Continuing its global migration, Honda built a factory in Ohio to manufacture CR250R Elsinore dirt bikes in 1979.

Shortly after the first motorcycle powered off the U.S. assembly line, a fax to headquarters in Japan urged, “Proceed with auto production.” Accord manufacturing commenced in 1982, years before other Japanese brands began building complete vehicles here. Forging ahead of the curve, Honda launched the first Japanese luxury brand in 1986 with Acura Integras and Legends. Five years later, Acura shot a missile across Ferrari’s bow by introducing the NSX, Japan’s first supercar.

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Mr. Honda celebrated the NSX’s 1989 introduction but died in 1991, well before this dream car left production in 2005. Copious tears shed for the loss of these two icons ensured that the NSX eventually would return. While Ferrari and other supercar makers remain in Acura’s gunsight, the new NSX’s PMC is near a town with a ZIP code but not so much as a post office.

PMC chief engineer Clement D’Souza beams with pride explaining his team consists of 108 dedicated associates, most of whom have worked at least 20 years for Honda. On this shop floor there are no ties or blue jeans; the standard apparel is instead white trousers and a white shirt labeled with each associate’s first name and the Honda logo. Eight team members assemble NSX engines at Honda’s Anna, Ohio, plant 40 miles to the west.

The Anna engine plant is Honda’s largest with more than a million engines per year built by 2800 workers. Three rooms are dedicated to assembling and testing the NSX’s 3.5-liter twin-turbo V-6. Proving that this powerhouse is steeped in racing technology, the block, heads, and bottom cover are cast by Grainger & Worrall and machined by Cosworth, two premier British motorsports firms.

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One associate spends nearly six hours assembling each engine. Honda engineers invented a special measuring gauge to select valvetrain shims with utmost precision. Every fastener is hand-started, and the final torque applied by a power tool is automatically displayed on a screen and recorded in a data bank.

After assembly is complete and the joint sealant has cured for three hours, each engine is passed to another associate for break-in on a dynamometer. While peak torque isn’t measured, this process revs the engine to 4000 rpm with varying loads for an hour or so to spare the owner the break-in task. This ensures that a brand-new NSX can be driven straight to the track without fear of engine damage.

One slight logistics complication is attributable to the NSX’s dry-sump lubrication system. Oil used during dynamometer testing is drained into a sealed container for reuse. After the engine is removed from the dyno and its permanent lubricant reservoir is installed, that same oil is poured back in, before the finished V-6 is shipped to the PMC.

Crankshaft balancing also happens after the dyno test, once the electric motor’s rotor and dual-mass flywheel have been installed. Nine holes drilled and tapped into the viscous damper are used to add a precise amount of balance weight. At the flywheel end of the crank, bolts available in three different weights further fine-tune balance.

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Honda spent a total of $70 million over four years refurbishing a 30-year-old warehouse and installing tools to create the PMC. That investment covers both the 200,000-square-foot manufacturing plant and an adjoining 115,000-square-foot building used to store finished cars.

The pristine white walls and speckled flooring tell you this is not your typical car-manufacturing plant. The air conditioning, brilliant lighting, glass interior walls, and operating-room cleanliness make this an ideal place to build high-end automobiles.

The spaceframe manufacturing area takes up roughly 25 percent of PMC’s floor space. After aluminum castings, extrusions, and stamped panels are loaded by hand into rotisserie fixtures, eight robotic tools apply 860 MIG (metal inert gas) and spot welds. Each fixture is programmed to rotate up to 360 degrees on cue for welding-arm access to all sides of the joint.

Six of the spaceframe castings are hollow, thin-wall components made using a special ablation process. Carefully timed blasts of water flush away some of the core sand to rapidly quench the molten aluminum, thereby optimizing the casting’s microstructure and mechanical properties.

To minimize the width of the NSX’s A-pillars, Honda selected ultra-high-strength steel for the rails that sweep from the base of the windshield over the side glass to the NSX’s B-pillars and also for the windshield header. Bolts and adhesives are used to join these parts to the otherwise aluminum spaceframe.

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Robotic tooling also creates the rolled hem flanges that join inner and outer hood, door, and hatch panels, all of which are aluminum. The NSX’s front and rear fenders are molded SMC (sheet molding compound) plastic. The standard roof is aluminum while a carbon-fiber panel is available for an extra $6000.

The spaceframe and body panels are completed in about 10 hours. After allowing time for the adhesives to cure, these components advance to the paint shop, which takes up 30 percent of PMC’s floor space. In lieu of the tugs used to move bulky subassemblies in most car plants, human-powered carts are used to transfer NSX parts. Some spaceframes visit the quality-confirmation center where measurement tools accurate to 0.002-inch check for conformity to design specifications.

To prep for painting, metal parts pass through 10 dip-tank stations to clean and rinse all surfaces before an electro-deposition coating is applied. The final stop is a 50-minute bake at 340 degrees Fahrenheit to cure this corrosion-resistant coating.

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Most of the exterior panel finish is applied robotically with electrostatic bells (cups spun at high speed to atomize the paint) in the interests of quality and consistency. The exception is the use of hand-spray guns for the molded-plastic honeycomb grilles adorning the front and the rear of the NSX. PMC experts contend that a human touch is necessary to guarantee an even piano-black coating to every nook and cranny. Eleven coats of primer and paint are used for the main panels. Including cure time, the painting process lasts two days. D’Souza calls starting production while developing eight exterior color choices a huge challenge for a low-volume manufacturer.

Final assembly consumes another 30 percent of PMC’s floor space. Associates install about 100 parts during a 62-minute stop at each of the 22 stations. (Contrast that with roughly one minute per station at Honda’s high-volume assembly plants.) At any given time, there are 14 cars in process, so the full final-assembly trip takes approximately that many hours.

Urethane adhesives, along with a few fasteners, hold the glass and body panels in place. All screws are started by hand then tightened with special synchronized-transducer wrenches that provide audible and visual feedback to the assemblers, as well as a record of the torque applied. The engine and transaxle assembly are carefully lifted into the spaceframe at one of the early stations. Exterior panels are attached last—after chassis parts, interior trim, controls, and seats have been installed—to minimize the chance of damage to the finish.

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Wheels and headlamps are aligned in the PMC’s vehicle-quality area. Honda applied for a dozen patents to cover some of the special tools used here. For example, mirrors used for wheel alignment attach to the center instead of the periphery of each wheel to avoid rim scratches and to ensure precision. A bucket seat rolls on rails beneath the car during alignment to comfortably support the associate responsible for adjusting the steering and suspension links. To provide a clear spectator view through the windows surrounding the intensely lit final-inspection area, some of the light fixtures can be lifted up and out of the way by a system of cables and linkages. A four-post shaker checks for loose components and suspension rattles. There’s a four-wheel chassis dynamometer to run the powertrain and the brakes through stress tests.

Start to finish, the total manufacturing process lasts 10 to 12 days. Working four 10-hour days per week, the PMC team is capable of building approximately 2000 NSXs per year. An estimated 800 cars are planned for U.S. customers during the first year of production commencing May 1. What’s undetermined is how many more will be needed for the 60 foreign countries also served by this plant.

About 18,700 original NSXs were produced during its 1991–2005 model-year run, half of which were sold in the United States. Considering the annual average, Acura will have its work cut out selling its new $168,400 (base price) supercar. Eventually offering a targa-roof edition could expand the take rate. In addition, we’d love to see a $100,000 NSX with a clutch pedal but no electric-propulsion components. (For more on the NSX’s powertrain, head here and here.)

The true believers are positive that the new NSX will be successful. When they squint their eyes just right on the way through the glass entry doors, they may see three supplementary letters next to the word “Dream”: B-I-G.